Day 7 - RegExp Discussion

I prefer this as my reference sheet. And the tester helped alot for understanding the matching set.

Here's some explanation for some regex on the email validation patterns you found during the class:

• [A-z0-9_%+-] : matching for all alphanumeric or the symbols (eg:  _%+-  ) in the set.
• [\w-] : Matches any word character for \w also it's equivalent to [A-Za-z0-9_], or matching of symbol 'dash'(eg: -)
• \. : matches for dot(.); Besides dot(.), characters/symbols that need escapes include:  $ ^ { [ ( | ) ] } * + ? \  which mean that if i want to find matches of + in a certain string, i'll need the pattern /    \+     /, for matches of dollar sign, i may need this pattern /    \$   / with the backslash in front of the symbol. For the other symbols that are not listed above eg:% ! @ < > / # ~ - _ ; : " ' ` backslash is not necessary in the pattern.
•  [a-zA-Z0-9_-] == [-A-Za-z0-9_] == [0-9_A-Za-z-] : if we split the patterns in the set, we can found a-z, A-Z, 0-9, underscore(_), dash(-); when we have them writing in a set, there would be no order for which should be written first.
• [^<>()[\]\\.,;:\s@\"] :
• the most complicated case above all
•  the ^(caret) that occur on the 1st place after the square bracket([]) has different meaning with the ^(caret) that place on the 1st place of a pattern.
• eg:  [^aeiou] :  Matches any single character not in the specified set of characters. 
• which means if the string doesn't not have these symbols ( < >( )[ ] . , ; @ \ " ) , it fulfills the match.
• \s : matches any white-space character. or it's equivalent to  [ \f\n\r\t\v] (eg: space, feed, new line, carriage return, tab, vertical tab)